Portable 230V Lamp Flasher

This is a portable, 230V high-power incandescent electric lamp flasher circuit diagram. It is actually basically a double flasher (alternating blinker) which could manage two different 230V AC loads (bulb lamps L1 and L2).

The circuit is completely transistorised and battery-powered. The free-running oscillator circuit is realised working with two low-power, low-noise transistors T1 and T2. One of these two transistors is constantly conducting, whilst the other is blocking. Because of normal charging and discharging of capacitors C1 and C2, both the transistors alternate between conduction and non-conduction states.

The collector of transistor T1 is joined to the base of driver transistor T4 via current-limiting resistor R5. In the same way, the collector of transistor T2 is joined to the base of driver transistor T3 via current-limiting resistor R6. These transistors are utilized to trigger Triac1 and Triac2 (each Triac is BT136 type) through optotriacs IC1 and IC2, correspondingly, and switch on the power supply to external loads L1 and L2. IC1 and IC2 work additionally at a low frequency decided by the values of capacitors C1 and C2.

The oscillator circuit designed close to transistors T1 and T2 produces low frequencies. When transistor T3 conducts, IC1 is enabled to fire Triac1 and bulb L1 glows. In the same way, when transistor T4 conducts, IC2 is enabled to fire Triac2 and bulb L2 glows.

Hook up the power supply line (L) of mains to bulbs L1 and L2, and neutral (N) to T1 terminals of Triac1 and Triac2. You can also connect neutral (N) line of the external 230V mains supply to both loads (bulbs L1 and L2) as a common line and then route supply line (L) to respective loads (bulbs L1 and L2).

The circuit operates off only 3 volts. Considering that electric current usage is relatively low, two AA-type cells are enough to supply the circuit. Assemble the circuit on a general-purpose PCB and enclose inside a appropriate plastic case with integrated AA-size pen-light cell holder. Drill holes for installing the “on”/”off” switch and power switching terminals. Also connect two bulb holders for bulb lamps L1 and L2. Refer to the following image for pin configurations.

WARNING. To prevent the dangerous electrical shock, please be careful while constructing, testing or repairing.